Adding backup drives in Windows Server Backup

AKA How to fix “The filename, directory name, or volume label syntax is incorrect.”

There’s a little bug in Windows 2008 and 2008 R2 that prevents adding a backup drive to an existing backup schedule unless you have all of the existing backup locations online.  What that means is that if you have, say, 5 USB drives that are used for backup and you wish to add another drive you will have to connect all of the drives at once.  This is often inconvenient, for want of cables, available USB ports and having all drives on hand.

Here’s an example of this error; we have run through the backup wizard and selected to add destinations / targets to an existing backup schedule:


This is a documented bug (MS KB 2009365), and the only real surprise is how persistent it is – the bug has been present since the first release of Windows Server 2008 and remains present in Server 2012!  (For 2012 there is a hotfix available – MS KB 2833738)

To work around this behaviour we will add the new disk(s) as backup targets using the command line wbadmin tool.  Fire up an administrative command prompt and connect the new backup disk, then run “wbadmin get disks >C:\Scripts\wbadmin-get-disks.txt”, which will output a text file like so:

Disk name: VMware Virtual disk SCSI Disk Device
Disk number: 0
Disk identifier: {3f102ddb-0000-0000-0000-000000000000}
Total space: 250.00 GB
Used space : 57.06 GB
Volumes: [System Reserved],C:[(no volume label)]
Disk name: PI-239 USB 2.0 Drive USB Device
Disk number: 1
Disk identifier: {d685afcf-0000-0000-0000-000000000000}
Total space: 465.76 GB
Used space : 465.74 GB
Volumes: [XenApp-1-Monday]

Now we can copy the relevant ‘Disk identifier’ value  {d685afcf-0000-0000-0000-000000000000} and use this to add the backup drive with:

wbadmin enable backup –addtarget: {d685afcf-0000-0000-0000-000000000000}

You’ll be prompted to confirm that you want to format the disk and add it to the list of backup targets.

You’re all done.

Reference: MS KB 2009365


  1. Graham Sivill

    Is there a way using the Wbadmin enable backup command that you can specify the name of teh target backup disk ie “BackupDisk1” or “MondayBackup”?

    • Admin

      No. What you can do is assign them letters and run WBAdmin against those, or use some scripting and findstr to automagically extract the Identifier from the wbadmin get-disks output.

  2. Kay

    Will I have a shadow copy of the first backup on the second backup or it will start backing files one the first backup disk is full and can I remove the first harddisk

    • Admin

      On each disk you end up with a VHD image of the protected disks and shadow copies to provide older versions of the backup. This behaviour has been the same with Windows Server Backup since Server 2008 and means you only need 1 disk to fully restore a backup.

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